LONDON (AFP) – Britain and Ireland called in Israel’s envoys on Thursday amid a growing diplomatic furor over the use of fake passports by the killers of a Hamas chief.

Israel’s ambassador to London, Ron Prosor, was asked to meet with a senior official at the Foreign Office, the day after Prime Minister Gordon Brown called for a “full investigation” into the passports row.

Irish Foreign Affairs Minister Micheal Martin called in Israel’s envoy for talks, saying he regarded the use of false Irish passports as “an extremely serious incident”.

“We are putting pretty direct questions and seeking assistance and clarification. We want to get answers as quickly as we possibly can,” added Martin.

Diplomatic tensions have mounted over the killing of Mahmud al-Mabhuh last month in a luxury Dubai hotel, ever since the emirate’s police chief revealed that 11 European passport holders were allegedly involved. Austria is now investigating whether Austrian telephones were used to plan the killing. Related article: Mossad’s forays abroad

No government has directly accused Israel but speculation about the killers has centred on Israel’s Mossad intelligence services, which have used agents with fake passports for such operations in the past.

Israeli Foreign Minister Avigdor Lieberman said Wednesday there was no evidence to suggest the Jewish state’s spies were responsible.

“There is no reason to think that it was the Israeli Mossad and not some other intelligence service or country up to some mischief,” he said.

Dubai’s police chief this week released the photos and names of the 11 European passport holders — six from Britain, three from Ireland, one from Germany and one from France — accused of being behind the murder.

All the countries except Germany have insisted the passports were faked.

Britain had abstained from talking about a possible Israeli link but on Wednesday said it wanted to clarify matters with Israel.

Prosor will hold talks with Peter Ricketts, the head of Britain’s diplomatic service.

Amid growing demands for answers from lawmakers, the British prime minister has promised a full investigation. “The British passport is an important document that has got to be held with care,” he said Wednesday. Related article: EU passports of Hamas murder suspects not fake: Dubai police

“The evidence has got to be assembled about what has actually happened and how it happened and why it happened.”

Britain’s Serious Organised Crime Agency will lead the probe in cooperation with the United Arab Emirates authorities, a government spokesman said.

In Ireland, Martin told RTE state radio that Israel’s ambassador had been told to attend a meeting at the foreign affairs ministry on Thursday and that Ireland wanted quick answers.

Ireland initially said the details of the three Irish passport holders were entirely false, but on Wednesday said that new information from the Dubai authorities suggested genuine Irish passport numbers were used.

“We have invested very heavily in the security of the Irish passport,” Martin said.

“It is a very important document. It has significant international credibility. Events like this undermine that and, most importantly, put the security of Irish citizens at risk.

In Austria meanwhile, authorities said they were investigating whether the killers used Austrian phone numbers or SIM cards to plan their hit. Related article: Stolen identities used by Hamas chief assassins

The Subscriber Identity Module (SIM) card, a portable memory chip, holds personal identity information, cell phone number, phone book, text messages and other data.

“Apparently Austrian phone numbers were used,” interior ministry spokesman Rudolf Gollia told AFP. “But we can’t say anything further. The investigations are underway and we’re in contact with Dubai police.”

Dubai police chief Dahi Khalfan has insisted the European passports found were not fakes, saying immigration officers in the emirate were trained to spot such documents, Al-Bayan newspaper reported Thursday.